An electric heating tube (or called a metal tubular electric heating element) is a charged element configured to convert electrical energy into thermal energy. Compared with conventional heating, the electric heating tube is pollution-free, convenient to install and use, cheap, and belongs to environmentally friendly green production, thus the electric heating tube is widely used. The electric heating tube may be applied in multiple types of devices which require heat exchange process. For example, multiple electric heating tubes may be combined into a heat exchange system to be installed in a fluid channel of a saltpeter tank, a water tank, an oil tank, an acid-alkali tank, a fusible metal melting furnace, an air heating furnace, a drying furnace, a drying oven, a hot die and other devices.
In the case that multiple electric heating tubes are installed in an annular fluid heat exchange transmission channel (a fluid channel) in a circular ring-shaped heating device, the multiple electric heating tubes are respectively connected to fixed ends of the electric heating tubes in the fluid channel to be fixed. Phases of the electrodes of the multiple electric heating tubes are required to be connected in series or in parallel to form a multiphase-load heat generation resource, and the multiple electric heating tubes are supplied with power via alternating current. Therefore, the electrodes of the electric heating tubes are required to be connected in a split-phase manner, connected in series or connected in parallel by means of the electrical connector, and further are connected with an external power supply. In this case, the electrical connector itself, in addition to transmitting the electric energy, is located in the channel where the fluid flows and becomes an obstacle in a flow path of the fluid-hot air, which may cause forced vibration of the electrical connector and even induce coupled vibration (i.e., resonance) of the electrical connector and the fluid, thereby causing the electrical connector to be prone to be disengaged and separated from the electrodes of the electric heating tube and thus causing a short-circuit fault.
In the conventional technology, in a method for addressing the above issue, the electrical connector is prevented from vibrating, that is, the electrical connectors (such as wires) connected to extraction electrodes of a number of branch electric heating tubes are configured to pass through and be extracted from the fluid channel directly in a radial direction of the fluid channel, and the extracted electrodes are connected in series or connected in parallel outside the fluid channel, which may cause many joints and make connection and fixing processes of external leads of a device complex. Moreover, in the case that the fluid in the fluid channel is liquid, a strict sealing process for preventing the fluid channel from leaking is further required. In another method for addressing the above issue, in the case that the fluid in the fluid channel is liquid, the electrical connector is not allowed to be extracted to the outside, and in this case, multiple electrical connectors must be connected in series or in parallel inside the fluid channel. In the case that insulation flexible leads are selected as the electrical connector for connecting the electrodes of the electric heating tubes, in order to prevent the leads from resonating in the fluid under the action of fluid pressure, the insulation leads are required to be fixed to an inner wall of the fluid channel, and after failure of insulation between insulation layers of the leads and the metal inner wall of the fluid channel, discharge of the electrical connector may be caused, resulting in a short-circuit fault of the entire heat exchange system.
Therefore, there is an urgent demand for a new electrical connector, a fluid state test device and a fluid heat exchange system.